journal of dentistry 42 (2014) 351–358
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Effective tooth-bleaching protocols capable of reducing H2O2 diffusion through enamel and dentine Diana G. Soares a, Fernanda G. Basso b, Elaine C.V. Pontes a, Lucas da F.R. Garcia c, Josimeri Hebling d, Carlos A. de Souza Costa c,* a
Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, Univ Estadual Paulista, Araraquara, SP, Brazil b Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas – UNICAMP, Piracicaba, SP, Brazil c Department of Physiology and Pathology, Araraquara School of Dentistry, Univ Estadual Paulista, Araraquara, SP, Brazil d Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, Univ Estadual Paulista, Araraquara, SP, Brazil
article info
abstract
Article history:
Objectives: To evaluate the effects of experimental protocols on bleaching effectiveness and
Received 15 May 2013
hydrogen peroxide (HP) diffusion through enamel and dentine.
Received in revised form
Methods: Enamel/dentine discs were subjected to six bleaching sessions, consisting of 1 or 3
30 July 2013
applications of 17.5% or 35%-HP gel for 5/15 min, or 37% carbamide peroxide (CP) gel for 10/
Accepted 10 September 2013
20 min. Discs undergoing the regular protocol (35%-HP; 3 15 min) constituted the positive control group. Colour change (DE) was assessed (CIE L*a*b* system) after each session. HP diffusion was quantified (sessions 1, 3, and 6) in enamel/dentine discs adapted to artificial
Keywords:
pulp chambers. Data were analysed by Pillai’s Trace and Bonferroni test, or by one-way
Tooth bleaching
ANOVA and SNK/Tamhane’s test (a = 5%).
Hydrogen peroxide
Results: All tooth-bleaching protocols significantly increased the DE values. A reduction in
Enamel
HP diffusion and no significant difference in DE compared with the positive control were
Dentine
observed for the following bleaching protocols: 17.5%-HP 3 15 min, at the 4th session; and 35%-HP 1 15 and 3 5 min, at the 5th session. HP diffusion in the 37%-CP 3 20 min bleaching protocol was statistically similar to that in the positive control. The other experimental bleaching protocols significantly decreased HP diffusion through enamel/ dentine discs, but the DE values were statistically lower than those observed in the positive control, in all sessions. Conclusion: Shortening the contact time of a 35%-HP gel or reducing its concentration produces gradual tooth colour change and reduced HP diffusion through enamel and dentine. Clinical significance: A reduction in HP concentration, from 35% to 17.5%, in a bleaching gel or shortening its application time on enamel provides a significant tooth-bleaching improvement associated with decreased HP diffusion across hard dental tissues. Therefore, these protocols may be an interesting alternative to be tested in the clinical situation. # 2013 Elsevier Ltd. All rights reserved.
* Corresponding author at: Department of Physiology and Pathology, Univ Estadual Paulista – UNESP, Araraquara School of Dentistry, Humaitá Street 1680, 14801-903 Araraquara, SP, Brazil. Tel.: +55 16 3301 6477; fax: +55 16 3301 6488. E-mail address: casouzac@foar.unesp.br (C.A. de Souza Costa). 0300-5712/$ – see front matter # 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jdent.2013.09.001